Plus — Definition, Formula & Examples
Plus is the word and symbol (+) used to show that two or more numbers are being added together. When you see 3 + 5, you read it as 'three plus five.'
The term 'plus' denotes the binary operation of addition, represented by the symbol , which combines two addends to produce their sum.
Key Formula
Where:
- = First addend (a number being added)
- = Second addend (a number being added)
- = Sum (the result of the addition)
How It Works
Place the sign between two numbers to show you are adding them. The numbers on each side of the are called addends, and the result is called the sum. You can chain several plus signs together, like , and add from left to right. The order of the addends does not change the sum, so gives the same answer as .
Worked Example
Problem: What is 12 + 25?
Step 1: Write the addition using the plus sign.
Step 2: Add the ones: 2 + 5 = 7. Add the tens: 10 + 20 = 30. Combine them: 30 + 7 = 37.
Answer: 12 plus 25 equals 37.
Why It Matters
Addition is one of the first operations you learn and appears in nearly every math course afterward. Counting money, measuring ingredients, and keeping score all rely on combining numbers with plus.
Common Mistakes
Mistake: Confusing the plus sign (+) with the multiplication sign (×), especially in handwriting.
Correction: The plus sign has two lines of equal length crossing at right angles. A multiplication sign is typically rotated so it looks like an ×, or it is written as a dot (·). Pay attention to the angle and context.